The PIENU experiment at the TRIUMF laboratory in Vancouver, Canada, aims to provide a high precision measurement of the pion decay branching ratio Rπ=Γ[π+→e+νe(γ)]/Γ[π+→μ+νμ(γ)], calculated within the standard model as RSMπ=(1.2352±0.0002)×10−4 with a precision of 0.016\%. Different scenarios for physics BSM such as the violation of lepton universality, new pseudoscalar interactions have an impact on Rπ. By measuring Rπ with a precision comparable to the prediction of the SM the sensitive structure of the weak interaction can be tested.

Between 2009 and 2012, PIENU accumulated 6.5 million π+→e+νe decays, operating at the M13 beamline at TRIUMF. The analysis of a subset of the 2010 data with 400 thousand events was published in 2015 in agreement with the SM with a precision of 0.24\%. Recent work has shown that the inclusion of additional 3.5 million events %(acquired between 2010 November and 2012) to the analysis increases the precision to 0.12\%. In this presentation we discuss the progress and prospects on the analysis of the remaining data.